import java.awt.*;
import java.awt.event.*;
import javax.swing.*;
import java.beans.*;
import java.util.Random;

public class ProgressBar extends JPanel implements ActionListener, PropertyChangeListener 
{
    private ProgressMonitor progressMonitor;
    private JTextArea taskOutput;
    private Task task;
    int progress;

    class Task extends SwingWorker<Void, Void> 
    {
        @Override
        public Void doInBackground() {
            Random random = new Random();
            int progress = 0;
            setProgress(0);
            try {
                Thread.sleep(1000);
                while (progress < 100 && !isCancelled()) {
                    //Sleep for up to one second.
                    Thread.sleep(random.nextInt(1000));
                    //Make random progress.
                    setProgress(Math.min(progress, 100));
                }
            } catch (InterruptedException ignore) {}
            return null;
        }

        @Override
        public void done() {
            Toolkit.getDefaultToolkit().beep();
            progressMonitor.setProgress(0);
        }
    }

    public ProgressBar() 
    {
        super(new BorderLayout());

        //Create the demo's UI.

        taskOutput = new JTextArea(5, 20);
        taskOutput.setMargin(new Insets(5,5,5,5));
        taskOutput.setEditable(false);

        add(new JScrollPane(taskOutput), BorderLayout.CENTER);
        setBorder(BorderFactory.createEmptyBorder(20, 20, 20, 20));

    }


    /**
     * Invoked when the user presses the start button.
     */
    public void actionPerformed(ActionEvent evt) {
        progressMonitor = new ProgressMonitor(ProgressBar.this,
                                  "Querying StaffLists",
                                  "", 0, 100);
        progressMonitor.setProgress(0);
        task = new Task();
        task.addPropertyChangeListener(this);
        task.execute();
    }

    public void setProgress(int i, int j)
    {
    	progress = i/j * 100;
    	taskOutput.append(i+" of " + j +" lecturers queried");
    }
    /**
     * Invoked when task's progress property changes.
     */
    public void propertyChange(PropertyChangeEvent evt) {
        if ("progress" == evt.getPropertyName() ) {
            int progress = (Integer) evt.getNewValue();
            progressMonitor.setProgress(progress);
            String message =
                String.format("Completed %d%%.\n", progress);
            progressMonitor.setNote(message);
            taskOutput.append(message);
            if (progressMonitor.isCanceled() || task.isDone()) {
                Toolkit.getDefaultToolkit().beep();
                if (progressMonitor.isCanceled()) {
                    task.cancel(true);
                    taskOutput.append("Task canceled.\n");
                } else {
                    taskOutput.append("Task completed.\n");
                }
            }
        }

    }

    /**
     * Create the GUI and show it.  For thread safety,
     * this method should be invoked from the
     * event-dispatching thread.
     */
    private static void createAndShowGUI() {
        //Create and set up the window.
        JFrame frame = new JFrame("Progress Bar");
        frame.setDefaultCloseOperation(JFrame.EXIT_ON_CLOSE);

        //Create and set up the content pane.
        JComponent newContentPane = new ProgressBar();
        newContentPane.setOpaque(true); //content panes must be opaque
        frame.setContentPane(newContentPane);

        //Display the window.
        frame.pack();
        frame.setVisible(true);
    }
}
